The broad objective of this research is the identification of the major parameters of voluntary behavior, using the study of hypnotic susceptibility and its motivational, developmental, and psycho- physiological correlates as an empirical point of departure from which some of the parameters of interest can be studied by rigorous experimental procedures. This proposal presents a systematic research program for investigating the social determinants of the development of hypnotic susceptibility, for relating susceptibility to social motivation, and for assessing some implications of susceptibility and its physiological correlates in the diagnosis and treatment of clinical disorders.